1. Field of the Invention
This invention relates to self-propelled tractor units generally having augers mounted thereon and operable to drill holes in the earth for purposes of implanting fence posts, utility poles, piles, bulkheads and the like.
2. Background of the Invention
In commercial self-propelled (e.g., tractor-mounted) posthole diggers presently in common use, the auger unit typically is integrally attached at the rear of the tractor, and is essentially a single-purpose piece of construction equipment. The auger is horizontally fixed in relation to the tractor, and is movable downwardly during the drilling operation. In practice, the machine operator locates the auger over the hole location by maneuvering the tractor itself precisely into position. A large percentage of posthole digging operations involve the placement of long stretches of aligned holes for fencing or utility posts, which means that between successive holes the operator must drive forward to the next hole, then back up, while turning to look backward and forward, in order to position the auger; a second operator may also be stationed at the rear of the machine to manipulate the auger controls during drilling. Various situations may physically interfere with this backward and forward system of maneuvering machinery. Among them are ditches, railroad tracks, travelled highway, streams, building structures, boulders, pits, etc. Thus, in some cases the tractor may not be able to back up to precisely the intendee location of the hole. Furthermore, this system is inefficient and time consuming.